Muffler



,Dec# 22, l936 R. J. MacKENzlE :j AL 2,055,232

MUFFLER Original Filed May 3, 1934 ATTORNEYS Patented Dec. 22, 1936 UNITED STATES MUFFLER Roy J. MacKenzie and Lucien L. Haas, Buffalo,

N. Y., assignors to Buffalo Pressed Steel Company, Buffalo, N. Y.

Original application May 3, 1934, Serial No. 723,735. Divided and this application July ZZ, 1936, Serial No. 91,810

8 Claims.

This invention relates to muiers of the kind used in silencing the exhaust of internal combustion engines.

One of the objects of this invention is to pro- ,15 vide a muiiler which is built in two separate sections or units and in which a resonator 'chamber of one section or unit is connected by means of a relatively small tube with a resonator chamber of another section or unit to produce a resonator effect equivalent to that of a much longersingle chamber. Another object is to provide a muffler comprising a plurality of short sections or units which are connected in such a vmanner as to silence 10W frequency sound waves which would otherwise require a much longer single resonator chamber. Further objects of the invention will appear from the following description and claims.

This is a division of our pending application No. 723,735, filed May 3, 1934.

In the accompanying drawing:

Fig. l is a longitudinal central sectional view of a. portion of a muiller, and Fig. 2 is a similar .view of the remaining portion of a muliler embodying this invention.

Fig. 3 is a transverse sectional View, on line 3-3, Fig. 2.

In the design of mulers forsilencing the eX- haust of internal combustion engines, it frequently happens that the engine produces low sounds having low frequency sound waves which require long resonator chambers to silence such `sounds by destructive interference. In some i cases, mufflers cannot be made of sufficient length to provide resonator chambers of the required lengths because of lack of a continuous space of suflicient length on the chassis of a vehicle to ac- -commodate mufllers of such length, and in some cases, it is not economical to make muiilers of the required length. In accordance with this inven- `tion, mulllers can be made of relatively short units or sections which can be connected in such g a manner as to produce the effect of resonator `chambers of greater length than the length of any one section or unit.

In Figs. 1 and 2 is shown a muilier formed in three sections A, B and C, but itwill be understood that the muiller may have only two sections `for more than three sections, if desired. The sections may be of any suitable construction, those shown in the drawings illustrating merely one embodiment of this invention. The section or unit A of the muftler is provided with an outer shell 5 provided at one end thereof with a head G having formed thereon a tubular 5 portion 1 to which an exhaust pipe leading from the engine `may be suitably secured in the usual manner. At the other end, the outer shell 5 is provided with an end head 8. The muiller is provided with an inner shell or conduit 9 terminating at one end in a tubular extension I of the 5 head 8 and having the other end thereof supported by means of a bale or intermediate head lII from an intermediate shell I2. Other baffles or intermediate heads I and I6 connect `'the inner shell or conduit with the intermediate shell 10 I2, and one end oi the intermediate shell may be telescoped within an annular shoulder I'I formed on the head 6. The inner shell or conduit is `provided with suitable perforations or apertures I8 oi any suitable or desired form, these apertures 15 being arranged in groups lengthwise of the inner conduit.

The construction described results in the formation of two high frequency resonator chambers 2|l and 2I formed between the inner conduit 20 and the intermediate shell, and a low frequency resonator chamber 22 formed partly between the outer and intermediate shells and partly between the outerl shell and the inner shell or conduit 9. 'Ihis latter chamber silences sound waves of low- 25 er frequency than those silenced by the high frequency resonator chambers and 2|.

The second section or unit B of the muiller includes an outer shell 25 and a head 26 having a tubular extension 2'I which may be connected 30 by means of a sleeve or short tube 28 with the tubular extension I0 of the head 8 of the section A of the muiiier. This section of the muffler is also provided with an inner shell or conduit 30, .one end of which telescopes within the tubular portion 21 of the head 26, and the other end of which telescopes within a tubular extension 3I of a head 32, Fig. 2. This section or unit of the -muiiler is also provided with an intermediate shell 33, one end of which is supported by means i of an annular shoulder 34 of the head 32, Fig. 2, and the other end is supported by a bale or v intermediate head 35 connecting the intermediate 'shell with the outer shell 25, the baffle having a series of apertures 36. The section or unit B is 45 also provided with baffles or intermediate heads 1.31 and 38 extending between the conduit 30 and the intermediate shell 33. The inner conduit is I provided with suitable apertures 39 also arranged in groups, one group of these apertures establishing communication between the conduit and a 'high frequency chamber 40 formed between the bailies 31 and 3B and another group of apertures establishing' communication with a high fre- Y quency chamber 4I formed between the baille 3355 the front end of the section B of the muffler is formed a chamber 43 between the inner and intermediate shells and the front end of this cham-'f ber opens into a chamber 44 formed between the head 26 andthe baille 35. It Willbe noted that the front end of the intermediate shell 33 extends about' an imperforate portion `45'of the inner shell or conduit which forms with the inf termediate shell a bottle neck or passage thro-ugh" which sound waves may pass from the chamber resonator chamber 46 formed between' the intermediate and outer shells and extending substantially throughout the lengthV of theV section B of, the muier. Any other bottle neck or other means for establishing communication between the tto 'intermediate shell 52, the outer shellA and the` conduit or inner shell being4 suitably supported on heads 53gand 54. The head'54'has a tubular Y extension connected by means of a short sleeve or tube 55 with the tubular extension 3| of the head shell Y 5I terminates in an annular shouldered`V portion 56 of the head 54. This head is preferably also provided with a tubular portion 51 to which the usual tailpipe may be connected. The inner and intermediate shells are connected by balles or intermediate heads 6U and 6l to form three high frequency chambers 63, 64 and 65. `The outerV and intermediate shells are also connecte'd by means of bales or intermediateV heads 66 and 61 which'form the space between these two shells'intol chambers 68 and 69, the baffle 61k having apertures 1B Vthrough whichsound waves may pass fromfthe apertures of that'portion of the :inner shell or conduit 5lwhich extends beyond the end of the inner shell 52. The sections or units B and C ofthe muffler are shown-in the accompanying drawing as con- `nected in such'a manner that thev outer chamber 46-of thesection B may operate in conjunction with the chamber 68 of the section Cof the muffler to produce a' compo-site resonator chamber having silencing effect upon low frequency sound waveswhich is equivalent to the silencing effect -which would be produced in a chamber of lgreater length than anyf'of the sections of the muffler. This may be accomplished in any suitable or desired mannen and in the construction illustrated, a tube or pipe15 of relatively small diameter is used for this purpose. This tube is suitably secured in flanged openings 16 and 11 formed in Vthe heads 32 and 53 of the sections B and C of the muflier. If desired, a number of such tubes orpipes may be used. As a result of this con- I struction; sound waves from themain current of `gases in the conduit 30 pass through the chamber 443 and the bottle neck 45 and through apertures `36 of the bafe"35-into the chamber 460i the sectionB of the-muier, and then through` the -V tubeV or pipe 15 intoY the chamber'ffofV the section C of the mufer, and such sound waves after :passing into these chambersare returnedinthe reverse direction into theinner conduit tosilence A.

Vcertain sound waves by destructivel interference. The-muffler described has the advantage that it is-of -the VVstraight Athrough type; inwhich the and the head 32 of this section of the muflier. At

gases pass from one end of the mulier to the other end thereof without change of direction Y and without encountering any serious resistance to their flow. High frequency sound waves are silenced by means of the several high frequency resonator chambers formed between the inner and lintermediateshells.4 'Sound Waves of somewhat lower frequencies are silenced 'in the chambers 22 and 69, and sound waves of very low fre-` quencies aresilenced by the combined action of vtheichambers 46 and 66. The muiiier is also readily adaptable forluse in connection with engines of different designsfsince the several chambers may be madeiof Vgreater length by locating the baffles as may befldsired. For example, the bafiie 66 in sectionlC ofthe muler may be positioned in different locations lengthwise of theV space between theouter and intermediate shells of this section of the muiiier so that the length ofthe chambers 68 and 66 may be varied to enable these-chambers to silenceisoundwaves of different frequencies;V The "length of the bottle neck 45 may also be varied as desired to further adapt thefch'ambers 46 and 68 to operate on different wavelengths. The construction described Y thus formsvdoublebottle neck chamberin'that the pipe 15 also forms'with thebh'ar'nber 68`a bottleneck type of lresonator chamberA and varia;- tions in thelength of the pipe15lalsovariesthe frequencies` of V47sound Vwaves silenced i by the Chambers i i. l .i K s The construction described-f is falso readily adaptableto various chassis'='desig`ns since the sleeves 28 and 35 connecting adjacent sections may, of course, be made of any Adesired length.L 35 `We claim asfour invention-zL 1. A'muler comprising a'plurality of sections andhavin'g a substantiallycontinuous gas-passage common to said sections,l a `pair of said sections arrangedadjace'nt 'to'each' other 'being provided with nested shellsand headsfforming res- 4 onancechambers, and la;- relatively sinall passage `extending frompnesectionto the other and`con`- necting the resonance chambers-of adjacentgsections to produce a composite`V resonance chamber. 2. A muiiier comprising at least'ftwo sections vand having a substantially continuousinner-passageffor gases and' sound waves extending through said sectionsyeacnsect-ion being provided with "intermediateand outershellsf4 surrounding said @-50 linner passage and-formingabout said passage Y intermediate and outerffchambers, the outer chamber of one of said sections' being connected to `receivesound lwaves from' saidfpassage and the outer chamberfin another section having no connection with the inner -ichamber or passage in its section, and a relatively small .tube connecting the outer chambers of -adjacentsections Y 3. A muffler comprising. atleast two'sections and having a substantially continuousfstraight-O passage for gases', eachf section having a pair` of shells arranged onewithin theother and `forming between them a` chambe'rgthe chamber of'Vv one' -of said sections being in communication with saidw. passage; and apas'sage ,extendingjfrom one sec- 5 Y tion to the'other andjconnecting saidfchambers. l 4'. A muffler hay/ings section-j povided'witnfa passage. for`V gases, fa "Shelli and :baffles 1 forminga resonator chamberueommunicating with saidpa'sl-f` i sage to permit waves'to pass to yandrfrom "70 Vsaid passage and .-chambenslfa second section formedy separately? from. Ysailijlrst section f and L having ashell and bafesjformng a chambenand r a tube connecties, ,saidzchambersaf said Seetells W5 to form said chambers into a composite resonator chamber.

5. A muiiier having a section, comprising a conduit for gases and having perforations, a shell surrounding said conduit and receiving sound waves through said perforations, another shell arranged about said last shell and forming therewith a resonator chamber communicating with said conduit to permit sound Waves to enter said conduit, a second section having walls forming a substantially closed chamber therein, and a tube connecting said last mentioned chamber and said resonator chamber to form a composite resonator chamber.

6. A muiiler comprising at least two sections, one of said sections having a conduit for gases, provided with perforations arranged in groups, a shell surrounding a group of perforations and also surrounding an imperforate part of said con duit, a second shell arranged about said first shell and forming therewith a chamber communicating with said conduit through the space between said rst shell and said imperforate part of said conduit to form a bottle neck type of resonator chamber, the other of said sections having Walls forming a substantially closed chamber,

and a tube connecting said last mentioned chamber with said resonator chamber to forni another bottle neck resonator chamber communicating with said first bottle neck resonator chamber.

'7. A muler formed of at least two sections, each of which has walls independent of the walls of the other section and forming a resonator chamber in each section, a conduit for conducting gases and sound waves, means for conducting sound waves from said conduit to one of said chambers, and a tubular member extending from one section to the other and connecting said resonator chambers.

8. A muier formed of at least two sections, each of which has walls independent of the Walls of the other section and forming a resonator chamber in each section, a conduit for conducting gases and sound waves, means for conducting sound waves from said conduit to one end of one of said resonator chambers, and a tubular member extending from the other end of said last mentioned resonator chamber to one end of the other resonator chamber in the other section.

ROY J. MACKENZIE. LUCIEN L. HAAS. 

